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HiveMQ MQTT Client is an MQTT 5.0 and MQTT 3.1.1 compatible and feature-rich high-performance Java client library with different API flavours and backpressure support
/*
* Copyright 2018-present HiveMQ and the HiveMQ Community
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.hivemq.client.internal.util.collections;
import com.hivemq.client.internal.annotations.NotThreadSafe;
import com.hivemq.client.internal.util.Pow2Util;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;
import java.util.Arrays;
import java.util.NoSuchElementException;
import java.util.function.Consumer;
import java.util.function.Function;
/**
* @author Silvio Giebl
*/
@NotThreadSafe
public class Index {
private static final int MAX_CAPACITY = 1 << 30;
public static class Spec {
private static final int DEFAULT_MIN_CAPACITY = 1 << 4;
private static final float DEFAULT_NODE_THRESHOLD_FACTOR = 0.25f;
final @NotNull Function keyFunction;
final int minCapacity;
final float nodeThresholdFactor;
public Spec(final @NotNull Function keyFunction) {
this(keyFunction, DEFAULT_MIN_CAPACITY, DEFAULT_NODE_THRESHOLD_FACTOR);
}
public Spec(final @NotNull Function keyFunction, final int minCapacity) {
this(keyFunction, minCapacity, DEFAULT_NODE_THRESHOLD_FACTOR);
}
public Spec(final @NotNull Function keyFunction, final float nodeThresholdFactor) {
this(keyFunction, DEFAULT_MIN_CAPACITY, nodeThresholdFactor);
}
public Spec(
final @NotNull Function keyFunction,
final int minCapacity,
final float nodeThresholdFactor) {
this.keyFunction = keyFunction;
this.minCapacity = minCapacity;
this.nodeThresholdFactor = nodeThresholdFactor;
}
}
private final @NotNull Spec spec;
private @Nullable Object @NotNull [] table;
private int size;
private int nodeCount;
private int nodeThreshold;
public Index(final @NotNull Spec spec) {
this.spec = spec;
final int minCapacityPow2 = 1 << Pow2Util.roundToPowerOf2Bits(spec.minCapacity);
table = new Object[minCapacityPow2];
calcThresholds(minCapacityPow2);
}
public int size() {
return size;
}
public @Nullable E put(final @NotNull E entry) {
return put(entry, true);
}
public @Nullable E putIfAbsent(final @NotNull E entry) {
return put(entry, false);
}
private @Nullable E put(final @NotNull E entry, final boolean overwrite) {
final Object[] table = this.table;
final K key = spec.keyFunction.apply(entry);
final int hash = key.hashCode();
final int index = hash & (table.length - 1);
final Object o = table[index];
if (o == null) {
table[index] = entry;
added();
return null;
}
if (o.getClass() == Node.class) {
Node node = (Node) o;
while (true) {
if ((node.hash == hash) && spec.keyFunction.apply(cast(node.value)).equals(key)) {
final Object nodeValue = node.value;
if (overwrite) {
node.value = entry;
}
return cast(nodeValue);
}
final Object next = node.next;
if (next.getClass() == Node.class) {
node = (Node) next;
} else {
final E e = cast(next);
final K nextKey = spec.keyFunction.apply(e);
if (nextKey.equals(key)) {
if (overwrite) {
node.next = entry;
}
return e;
}
node.next = new Node(nextKey.hashCode(), next, entry);
added();
addedNode();
return null;
}
}
}
final E e = cast(o);
final K oKey = spec.keyFunction.apply(e);
if (oKey.equals(key)) {
if (overwrite) {
table[index] = entry;
}
return e;
}
table[index] = new Node(oKey.hashCode(), o, entry);
added();
addedNode();
return null;
}
public @Nullable E get(final @NotNull K key) {
final Object[] table = this.table;
final int hash = key.hashCode();
final int index = hash & (table.length - 1);
final Object o = table[index];
if (o == null) {
return null;
}
if (o.getClass() == Node.class) {
Node node = (Node) o;
while (true) {
if ((node.hash == hash) && spec.keyFunction.apply(cast(node.value)).equals(key)) {
return cast(node.value);
}
final Object next = node.next;
if (next.getClass() == Node.class) {
node = (Node) next;
} else {
final E e = cast(next);
if (spec.keyFunction.apply(e).equals(key)) {
return e;
}
return null;
}
}
}
final E e = cast(o);
if (spec.keyFunction.apply(e).equals(key)) {
return e;
}
return null;
}
public @Nullable E remove(final @NotNull K key) {
final Object[] table = this.table;
final int hash = key.hashCode();
final int index = hash & (table.length - 1);
final Object o = table[index];
if (o == null) {
return null;
}
if (o.getClass() == Node.class) {
Node node = (Node) o;
if ((node.hash == hash) && spec.keyFunction.apply(cast(node.value)).equals(key)) {
table[index] = node.next;
removedNode();
removed();
return cast(node.value);
}
Object next = node.next;
if (next.getClass() != Node.class) {
final E e = cast(next);
if (spec.keyFunction.apply(e).equals(key)) {
table[index] = node.value;
removedNode();
removed();
return e;
}
return null;
}
Node prevNode;
while (true) {
prevNode = node;
node = (Node) next;
if ((node.hash == hash) && spec.keyFunction.apply(cast(node.value)).equals(key)) {
prevNode.next = node.next;
removedNode();
removed();
return cast(node.value);
}
next = node.next;
if (next.getClass() != Node.class) {
final E e = cast(next);
if (spec.keyFunction.apply(e).equals(key)) {
prevNode.next = node.value;
removedNode();
removed();
return e;
}
return null;
}
}
}
final E e = cast(o);
if (spec.keyFunction.apply(e).equals(key)) {
table[index] = null;
removed();
return e;
}
return null;
}
public void clear() {
if (size > 0) {
if (table.length == spec.minCapacity) {
Arrays.fill(table, null);
} else {
table = new Object[spec.minCapacity];
}
size = 0;
nodeCount = 0;
calcThresholds(spec.minCapacity);
}
}
public @NotNull E any() {
for (final Object o : table) {
if (o != null) {
if (o.getClass() == Node.class) {
final Node node = (Node) o;
return cast(node.value);
}
return cast(o);
}
}
throw new NoSuchElementException();
}
public void forEach(final @NotNull Consumer consumer) {
for (final Object o : table) {
if (o != null) {
if (o.getClass() == Node.class) {
Node node = (Node) o;
while (true) {
consumer.accept(cast(node.value));
final Object next = node.next;
if (next.getClass() == Node.class) {
node = (Node) next;
} else {
consumer.accept(cast(next));
break;
}
}
} else {
consumer.accept(cast(o));
}
}
}
}
private void added() {
size++;
}
private void addedNode() {
if ((++nodeCount > nodeThreshold) && (table.length < MAX_CAPACITY)) {
final Object[] oldTable = table;
final int oldCapacity = oldTable.length;
final int newCapacity = oldCapacity << 1;
final int newMask = newCapacity - 1;
final Object[] newTable = new Object[newCapacity];
int newNodeCount = 0;
for (int oldIndex = 0; oldIndex < oldCapacity; oldIndex++) {
final Object o = oldTable[oldIndex];
if (o != null) {
if (o.getClass() == Node.class) {
Node node = (Node) o;
Node low = null, prevLow = null;
Node high = null, prevHigh = null;
final int highIndex = oldIndex + oldCapacity;
while (true) {
if ((node.hash & newMask) == oldIndex) {
if (low == null) {
low = node;
newTable[oldIndex] = node;
} else {
prevLow = low;
low = node;
prevLow.next = low;
}
} else {
if (high == null) {
high = node;
newTable[highIndex] = node;
} else {
prevHigh = high;
high = node;
prevHigh.next = high;
}
}
newNodeCount++;
final Object next = node.next;
if (next.getClass() == Node.class) {
node = (Node) next;
} else {
final E e = cast(next);
if ((spec.keyFunction.apply(e).hashCode() & newMask) == oldIndex) {
if (low == null) {
newTable[oldIndex] = e;
} else {
low.next = e;
}
if (high != null) {
if (prevHigh == null) {
newTable[highIndex] = high.value;
} else {
prevHigh.next = high.value;
}
newNodeCount--;
}
} else {
if (high == null) {
newTable[highIndex] = e;
} else {
high.next = e;
}
if (low != null) {
if (prevLow == null) {
newTable[oldIndex] = low.value;
} else {
prevLow.next = low.value;
}
newNodeCount--;
}
}
break;
}
}
} else {
final int hash = spec.keyFunction.apply(cast(o)).hashCode();
final int newIndex = hash & newMask;
newTable[newIndex] = o;
}
}
}
table = newTable;
nodeCount = newNodeCount;
calcThresholds(newCapacity);
}
}
private void removedNode() {
nodeCount--;
}
private void removed() {
if ((--size < nodeThreshold) && (table.length > spec.minCapacity)) {
final Object[] oldTable = table;
final int oldCapacity = oldTable.length;
final int newCapacity = oldCapacity >> 1;
final Object[] newTable = new Object[newCapacity];
int newNodeCount = nodeCount;
System.arraycopy(oldTable, 0, newTable, 0, newCapacity);
for (int oldIndex = newCapacity; oldIndex < oldCapacity; oldIndex++) {
final Object old = oldTable[oldIndex];
if (old != null) {
final int newIndex = oldIndex - newCapacity;
final Object o = newTable[newIndex];
if (o == null) {
newTable[newIndex] = old;
} else if (o.getClass() == Node.class) {
Node node = (Node) o;
Object next;
while (true) {
next = node.next;
if (next.getClass() == Node.class) {
node = (Node) next;
} else {
break;
}
}
node.next = new Node(spec.keyFunction.apply(cast(next)).hashCode(), next, old);
newNodeCount++;
} else {
newTable[newIndex] = new Node(spec.keyFunction.apply(cast(o)).hashCode(), o, old);
newNodeCount++;
}
}
}
table = newTable;
nodeCount = newNodeCount;
calcThresholds(newCapacity);
}
}
private void calcThresholds(final int capacity) {
nodeThreshold = (int) (capacity * spec.nodeThresholdFactor);
}
private @NotNull E cast(final @NotNull Object o) {
//noinspection unchecked
return (E) o;
}
private static class Node {
final int hash;
@NotNull Object value;
@NotNull Object next;
Node(final int hash, final @NotNull Object value, final @NotNull Object next) {
this.hash = hash;
this.value = value;
this.next = next;
}
}
}